Invertible microfeature device packages and associated methods

ABSTRACT

Invertible microfeature device packages and associated methods for manufacture and use are disclosed. A package in accordance with one embodiment includes a microfeature device having a plurality of device contacts, and a conductive structure electrically connected to the contacts. The conductive structure can have first and second package contacts accessible for electrical coupling to at least one device external to the package, with the first package contacts accessible from a first direction and the second package contacts configured to receive solder balls and accessible from a second direction opposite the first. An encapsulant can be disposed adjacent to the microfeature device and the conductive structure and can have apertures aligned with the second package contacts to contain solder balls carried by the second package contacts. Accordingly, the package can be connected in either a face-up or face-down orientation, and/or can be connected to another, similar device in either a face-to-face arrangement or a back-to-back arrangement.

TECHNICAL FIELD

The present invention relates generally to invertible microfeaturedevice packages and associated methods for manufacturing and installingsuch packages.

BACKGROUND

Microfeature devices, such as memory chips, are typically incorporatedinto a device package prior to installation in an end product. Thepackage can include an encapsulant that protects the chip, and aleadframe that connects chip terminals (located on the chip andsurrounded by the encapsulant) with package terminals that areaccessible from outside the package. The package terminals canaccordingly provide for communication between the chip and deviceslocated external to the package.

The package terminals are typically arranged in a pattern that conformsto industry developed standards, so that the package is installable in awide variety of electronic devices. Such standards have been developedfor ball grid array (BGA) arrangements and quad flat no-lead (QFN)plastic package arrangements. However, device packages manufactured tobe compatible with one standard attachment arrangement are typically notcompatible with others. Accordingly, the versatility of such devicepackages is limited, and package manufacturers and suppliers musttherefore manufacture and inventory packages compatible with a multitudeof attachment arrangements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C illustrate a method for attaching a microfeature device to aconductive structure in accordance with an embodiment of the invention.

FIG. 2 is an isometric illustration of a portion of a microfeaturedevice attached to a conductive structure in accordance with anembodiment of the invention.

FIGS. 3A-3C illustrate a method for packaging the microfeature deviceand the conductive structure shown in FIGS. 1A-2.

FIGS. 4A and 4B illustrate opposing outwardly facing surfaces of apackage formed in accordance with an embodiment to the invention.

FIGS. 5A-5B illustrate a microfeature device package attached to asupport member in two positions, one inverted relative to the other.

FIG. 6 is a partially schematic, cross-sectional illustration of adevice package having two microfeature devices stacked in accordancewith an embodiment of the invention.

FIG. 7 is a partially schematic, cross-sectional side view of a devicepackage having microfeature devices stacked in accordance with anotherembodiment of the invention.

FIG. 8 is a block diagram illustrating features of a system thatincorporates one or more packaged microfeature devices in accordancewith an embodiment of the invention.

DETAILED DESCRIPTION

A. Introduction

The present invention is directed to invertible microfeature devicepackages and associated methods for manufacturing and installing suchpackages. The term “microfeature device” is used throughout to include adevice formed from a substrate upon which and/or in which submicroncircuits or components, and/or data storage elements or layers arefabricated. Submicron features in the substrate include, but are notlimited to, trenches, vias, lines, and holes. These features typicallyhave a submicron width (e.g., ranging from, for example, 0.1 micron to0.75 micron) generally transverse to a major surface (e.g., a front sideor a back side) of the device. The term microfeature device is also usedto include substrates upon which and/or in which micromechanicalfeatures are formed. Such features include read/write head features andother micromechanical features having submicron or supramicrondimensions. In any of these embodiments, the substrate is formed fromsuitable materials, including ceramics, and may support layers and/orother formations of other materials, including but not limited tometals, dielectric materials and photoresists.

A microfeature device package system in accordance with one aspect ofthe invention includes a microfeature device, a plurality of devicecontacts electrically coupled to structures within the microfeaturedevice, and a conductive structure electrically connected to at leastone of the plurality of device contacts. The conductive structure canhave a plurality of first and second package contacts accessible forelectrical coupling to at least one device external to the package. Thefirst package contacts can be accessible from a first direction forcoupling, and the second package contacts can be configured to receivesolder balls and can be accessible from a second direction for coupling,the second direction being opposite the first direction. An encapsulantcan be disposed adjacent to the microfeature device and the conductivestructure, and can have apertures with aperture walls aligned with thesecond package contacts to contain solder balls carried by the secondpackage contacts. Accordingly, the packaged microfeature device can beoriented in one direction for coupling to one type of substrate, and canbe inverted for coupling to another type of substrate for which solderballs provide the intervening electrical connection.

A microfeature device package in accordance with another aspect of theinvention includes a first microfeature device having a plurality offirst device contacts and a second microfeature device having aplurality of second device contacts. The second microfeature device iscoupleable to the first microfeature device in either of twoorientations wherein in a first orientation the second device contactsface toward the first device contacts, and in a second orientation thefirst and second device contacts face in opposite directions. Aconductive structure is positioned at least proximate to the first andsecond microfeature devices and is electrically connected to at leastone of the first device contacts and to at least one of the seconddevice contacts.

A method for forming a microfeature device package in accordance withanother aspect of the invention includes disposing a conductivestructure at least proximate to a microfeature device, with theconductive structure having a plurality of first and second packagecontacts. The microfeature device can further have a plurality of devicecontacts electrically coupled to structures within the microfeaturedevice. The method can further include orienting the conductivestructure with the first and second package contacts accessible forelectrical coupling to devices external to the package. The firstpackage contacts can be accessible from a first direction for couplingand the second package contacts can be accessible from a seconddirection for coupling, with the second direction opposite the firstdirection. The method can further include electrically coupling theconductive structure to the device contacts of the microfeature device,and disposing an encapsulant adjacent to the conductive structure. Theencapsulant can include apertures aligned with the second packagecontacts, and aperture walls positioned to contain solder balls at thesecond package contacts.

B. Methods and Apparatuses in Accordance with the Embodiments of theInvention

Specific details of the invention are set forth in the followingdescription and in FIGS. 1A-8 to provide a thorough understanding ofcertain embodiments of the invention. One skilled in the art, however,will understand that the present invention may have additionalembodiments, and that other embodiments of the invention may bepracticed without several of the specific features explained in thefollowing description.

FIGS. 1A-1C are partially schematic, cross-sectional side viewsillustrating initial portions of a process for forming a package inaccordance with an embodiment of the invention. Referring first to FIG.1A, the package can include a conductive structure 120, for example, aleadframe 121 having a plurality of leadfingers 122. Each leadfinger caninclude a first end portion 123 a, a second end portion 123 b, and anintermediate portion 124 between the end portions 123 a, 123 b. Thefirst end portion 123 a can include an end surface 125 facing in a firstdirection A and the intermediate portion 124 can face in a seconddirection B, opposite the first direction A. As described in greaterdetail below, the end surfaces 125 can form first package contacts 113accessible from the first direction A, and the intermediate portions 124can form second package contacts 114 accessible from the seconddirection B. The second end portions 123 b can support tape strips 111or other adhesive media for attachment to a microfeature device, asdescribed in greater detail below with reference to FIG. 1B.

Referring now to FIG. 1B, a microfeature device 130 can be attached tothe tape strips 111 prior to being electrically coupled to theconductive structure 120. In one aspect of the embodiment, themicrofeature device 130 can include a memory device and in otherembodiments, the microfeature device 130 can include another type ofdevice, for example, a processor device. In any of these embodiments,the microfeature device 130 can include a first surface 131 facing inthe first direction A, and a second surface 132 facing in the seconddirection B. Device contacts 133 (e.g., bond pads) can be positioned ator proximate to the second surface 132 to provide for electricalcommunication between the conductive structure 120 and structures orfeatures located within the microfeature device 130.

Referring now to FIG. 1C, the microfeature device 130 and the conductivestructure 120 can be inverted as a unit. Wirebonds 112 can then beconnected between the second end portions 123 b of the leadfingers 122and the device contacts 133 to provide for electrical communicationbetween the microfeature device 130 and the conductive structure 120. Inother embodiments, conductive pathways between the device bond pads 133and the conductive structure 120 are formed from other connectingelements.

FIG. 2 is a partially schematic, isometric illustration of a portion ofthe microfeature device 130 and the conductive structure 120 describedabove with reference to FIGS. 1A-1C. As shown in FIG. 2, the conductivestructure 120 can include a first terminal portion 126 and a secondterminal portion 127. The first terminal portion 126 can include thefirst package contacts 113 facing in the first direction A, and thesecond terminal portion 127 can include the second package contacts 114facing in the second direction B. In one aspect of this embodiment, thefirst package contacts 113 include the generally flat end surfaces 125of the leadfingers 122. The second package contacts 114 can includeflat, disk-shaped surfaces of the leadfinger intermediate portions 124.In other embodiments, the first package contacts 113 and the secondpackage contacts 114 can have different shapes that also face inopposing directions, and (as described in greater detail below) supportsolder ball connections at the second package contacts 114 and otherconnections, including QFN connections, at the first package contacts113.

Referring now to FIG. 3A, the microfeature device 130 and the conductivestructure 120 can next be at least partially surrounded with anencapsulant 140. In a particular aspect of this embodiment, theencapsulant 140 can include apertures 141 aligned with the secondpackage contacts 114. In one embodiment, the apertures 141 are etched orotherwise formed in the encapsulant 140 after the encapsulant 140 hasbeen disposed over the conductive structure 120 and the microfeaturedevice 130. In another embodiment, the apertures 141 are formed in theencapsulant 140 as the encapsulant is disposed over the conductivestructure 120 and the microfeature device 130. In either embodiment, theapertures 141 can include aperture walls 142 positioned adjacent to thesecond package contacts 114 to support solder balls, as described belowwith reference to FIG. 3B.

Referring now to FIG. 3B, solder balls 115 can be disposed on theintermediate portions 124 of the lead fingers 122 through the apertures141 of the encapsulant 140. Accordingly, the solder balls 115 can form aconductive portion of the second package contacts 114. In one aspect ofthis embodiment, the solder balls 115 can be disposed as part of thepackage manufacturing process. In another embodiment, the solder balls115 can be disposed in a post-manufacture step. In still a furtherembodiment, the solder balls 115 can be eliminated (for example, whenonly the first package contacts 113 will be coupled to external devices)although the second package contacts 114 can remain configured tosupport the solder balls 115.

Referring next to FIG. 3C, a complete package 110 can be formed bysingulating the conductive structure 120 from adjacent conductivestructures (not shown), which are connected to other microfeaturedevices 130. The singulation process can also reduce an overall width ofthe package 110, while leaving the first package contacts 113 accessiblefor coupling to external devices from the first direction A, and thesecond package contacts 114 accessible for coupling to external devicesfrom the second direction B.

FIG. 4A is a plan view of an embodiment of the package described abovewith reference to FIG. 3C, as seen from the first direction A. As shownin FIG. 4A, the first package contacts 113 can be disposed around theperiphery of the package 110 to form a first pattern 150A (e.g., a QFNarrangement). Accordingly, the first package contacts 113 are suitablefor coupling to other devices compatible with a standard QFN contactarrangement. As is also shown in FIG. 4A, the first surface 131 of themicrofeature device 130 can be exposed (or can remain exposed) after theprocess of forming the package 110 has been completed. Accordingly, therate at which heat is transferred away from the microfeature device 130can be enhanced by virtue of the increased exposed surface area of thefirst surface 131.

FIG. 4B is a plan view of an embodiment of the package 110 describedabove with reference to FIG. 3C, as seen from the second direction B. Asshown in FIG. 4B, the second package contacts 114 can be disposedinwardly from the edges of the package 110 and can form a second pattern150 b that is different than the first pattern 150 a described abovewith reference to FIG. 4A. The second pattern 150 b can be suitable forcoupling the package 110 to devices having a standard BGA interface.

FIGS. 5A and 5B illustrate the package 110 connected to support memberswhile in each of two oppositely facing orientations, in accordance withan embodiment of the invention. Referring first to an embodiment shownin FIG. 5A, the package 110 can be positioned proximate to a supportmember 160 a with the first surface 131 of the microfeature device 130and the first package contacts 113 facing toward the support member 160a. The support member 160 a can include an external terminal portionthat includes support member bond pads 161 a aligned with thecorresponding first package contacts 113. Solder paste 162 can bedisposed between the first package contacts 113 and the support memberbond pads 161 a to electrically couple the package 110 to the supportmember 160 a, using standard QFN bonding techniques. In one embodiment,the support member 160 a can include a printed circuit board havinginternal and/or surface mounted circuitry, and in other embodiments, thesupport member 160 a can include other devices. When the package 110 isconnected to the support member 160 a in the manner shown in FIG. 5A,the solder balls 115 can be eliminated because the connection betweenthe package 110 and the support member 160 a is provided by the firstpackage contacts 113.

Referring now to FIG. 5B, a device package 110 having exactly the sameconfiguration as that shown in FIG. 5A can be inverted so that thesecond package contacts 114 and the second surface 132 of themicrofeature device 130 face toward a support member 160 b. The supportmember 160 b can include support member bond pads 161 b arranged in astandard BGA pattern. Accordingly, the solder balls 115 can be connectedbetween the second device package 110 and the support member bond pads161 b using standard BGA bonding techniques to provide for theelectrical link between the support member 160 b and the microfeaturedevice 130.

One feature of an embodiment of the microfeature device package 110described above with reference to FIGS. 1A-5B is that the package 110has different types and arrangements of package contacts. Accordingly,the package 110 can be placed in a first orientation to connect to adevice having a first coupling arrangement (for example, aQFN-compatible device) and can be inverted for attachment to a devicehaving a different type of attachment arrangement (for example, aBGA-compatible device). An advantage of this feature is that the samepackage 110 can be used in either installation. Accordingly, amanufacturer need not maintain separate production lines or separateinventories of packages suitable for coupling to external devices havingdifferent types of coupling arrangements. As a result, the cost forproducing the microfeature devices 110 can be reduced when compared withthe cost of producing existing devices.

FIG. 6 is a partially schematic, cross-sectional side elevation view ofa stacked device package 610 that includes two microfeature devices 130,shown in FIG. 6 as a first microfeature device 130 a and a secondmicrofeature device 130 b. In one aspect of this embodiment, the firstmicrofeature device 130 a is installed in a first package 110 a, and thesecond microfeature device 130 b is installed in a second package 110 b.The packages 110 a, 110 b can be generally similar to the package 110described above with reference to FIGS. 1A-5B. In other embodiments, thepackages 110 a, 110 b can have other arrangements. In a particularembodiment, second package contacts 114 a of the first package 110 a arearranged to form a mirror image of the second package contacts 114 b ofthe second package 110 b. Accordingly, output signals from one of thepackages 110 a, 110 b can provide input signals to the other package. Inany of the foregoing embodiments, the first microfeature device 130 aand the second microfeature device 130 b are electrically coupled toeach other with a conductive structure 620, as described below.

In one aspect of this embodiment, the conductive structure 620 canextend between and around the microfeature devices 130 a, 130 b. In aparticular aspect of this embodiment, the conductive structure 620 caninclude a first leadframe 121 a (which can form a portion of the firstpackage 110 a) and a second leadframe 121 b (which can form a portion ofthe second package 110 b). In a further particular aspect of thisembodiment, the first microfeature device 130 a and the secondmicrofeature device 130 b are oriented so that a second surface 132 a ofthe first microfeature device 130 a faces toward a second surface 132 bof the second microfeature device 130 b. Accordingly, first device bondpads 133 a of the first microfeature device 130 face toward seconddevice bond pads 133 b of the second microfeature device 130, and afirst surface 131 a of the first microfeature device 130 a faces awayfrom a first surface 131 b of the second microfeature device 130 b. Inanother embodiment, the orientations of the first and secondmicrofeature devices 130 a, 130 b can be inverted, for example, asdescribed in greater detail below with reference to FIG. 7. In eitherembodiment, the stacked device package 610 can include couplers 616 thatelectrically connect the first microfeature device 130 a to the secondmicrofeature device 130 b. For example, the couplers 616 can includesolder balls connected between the first leadframe 121 a and the secondleadframe 121 b. In other embodiments, the couplers 616 can includeother conductive structures.

In one aspect of an embodiment shown in FIG. 6, the stacked devicepackage 610 includes two arrays 613 of first package contacts 113, shownas a first array 613 a and a second array 613 b. Both package contactarrays 613 a, 613 b have similar or identical layouts. Accordingly, thestacked device package 610 can be positioned with either the firstcontact array 613 a or the second contact array 613 b facing toward asupport member 660. The support member 660 can include support memberbond pads 661 positioned to make electrical contact with either thefirst contact array 613 a or the second contact array 613 b. Solderpaste 662 or another conductive medium can provide for physical andelectrical coupling between the contact array 613 and the support memberbond pads 661.

FIG. 7 is a cross-sectional side elevation view of a stacked devicepackage 710 having the first and second packages 110 a, 110 b stacked inan arrangement that is inverted from that shown in FIG. 6. Accordingly,the first surface 131 a of the first microfeature device 130 a facestoward the first surface 131 b of the second microfeature device 130 b,and the second surfaces 132 a, 132 b of the devices 130 a, 130 b faceaway from each other. As a result, it is the second package contacts 114a, 114 b (arranged in two arrays 714 a, 714 b) that are exposed forcoupling to a support member 760. Couplers 716 (e.g., solder pastecouplers) can physically and electrically connect the first leadframe121 a to the second leadframe 121 b to form the conductive structure720. In another embodiment, the conductive structure 720 can have otherarrangements. In any of these embodiments, either of the contact arrays714 a, 714 b can be aligned with corresponding support member bond pads761 to provide for physical and electrical communication between thesupport member 760 and the stacked device package 710.

One feature of the stacked device packages described above withreference to FIGS. 6 and 7 is that the microfeature devices 130 arepositioned either face-to-face or back-to-back, for example, either withthe first surfaces 131 a, 131 b facing toward each other, or with thefirst surfaces 131 a, 131 b facing in opposite directions. One advantageof this feature is that the exposed package contacts can have the samearrangement, whether the package is face up or face down. Accordingly,the effort required to correctly orient the stacked device package forcoupling to the support member can be reduced when compared withexisting devices.

FIG. 8 is a block diagram illustrating components of a system 800 inwhich one or more packages of the type described above with reference toFIGS. 1A-7 can be incorporated. In one aspect of this embodiment, thesystem 800 includes a processor 801 coupled to an input device 803 andan output device 804. The processor 801 can also be coupled to a memorymodule 802. In one aspect of this embodiment, the system 800 includes acomputer and in other embodiments, the system 800 can include otherdevices, for example, a telecommunication device. In any of theseembodiments, the system 800 can include one or more packages 810incorporated, for example, in the processor 801 and/or in the memorymodule 802. The packages 810 can have a stacked arrangement (generallysimilar to that described above with reference to FIGS. 6 and 7) or anunstacked arrangement (generally similar to that described above withreference to FIGS. 1A-5B). In either embodiment, the packages can bemounted to a support member (e.g., a printed circuit board) inaccordance with any of the arrangements described above. In any of theforegoing embodiments, the packages 810 can be more easily integratedinto the system 800, as described above, and can have a reduced costwhen compared with conventional packages, also as described above.Accordingly, the system 800 can be less expensive to manufacture thanconventional systems.

From the foregoing, it will be appreciated that specific embodiments ofthe invention have been described herein for purposes of illustration,but that various modifications may be made without deviating from thespirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1-11. (canceled)
 12. A microfeature device package, comprising: a microfeature device having an at least generally planar first surface facing a first direction and an at least generally planar second surface facing a second direction opposite from the first direction; first and second device contacts positioned proximate to the second surface of the microfeature device, the device contacts being electrically coupled to structures within the microfeature device; a conductive leadframe positioned at least proximate to the second surface of the microfeature device, the leadframe having first and second elongated leadfingers, each of the first and second leadfingers having a first end surface, a second end surface, and a generally flat intermediate surface between the first and second end surfaces, each first end surface having a first package contact facing in the first direction, each intermediate surface having a second package contact facing in the second direction; a first wirebond connected between the first device contact and the first leadfinger; a second wirebond connected between the second device contact and the second leadfinger; and an encapsulant disposed adjacent to the microfeature device and the leadframe, the encapsulant having apertures aligned with the second package contacts, the apertures having aperture sidewalls positioned to contain solder balls at the second package contacts, the first and second package contacts being accessible for coupling to devices external to the package, the first package contacts being accessible for coupling from the first direction, and the second package contacts being accessible for coupling from the second direction.
 13. The package of claim 12, further comprising: a first solder ball disposed on the intermediate surface of the first leadfinger; and a second solder ball disposed on the intermediate surface of the second leadfinger.
 14. The package of claim 12 wherein the first contacts are arranged in a first pattern and the second contacts are arranged in a second pattern different than the first pattern.
 15. The package of claim 12 wherein the microfeature device includes a first microfeature device, and wherein the package further comprises a second microfeature device stacked relative to the first microfeature device and electrically connected to the conductive leadframe.
 16. A microfeature device package, comprising: a first microfeature device having a plurality of first device contacts; a second microfeature device having a plurality of second device contacts, the second microfeature device being coupleable to the first microfeature device in either of two orientations, wherein in a first orientation, the second device contacts face toward the first device contacts and in a second orientation, the first and second device contacts face in opposite directions; and a conductive structure positioned at least proximate to the first and second microfeature devices, the conductive structure being electrically connected to at least one of the first device contacts and to at least one of the second device contacts.
 17. The package of claim 16 wherein the conductive structure includes: a first leadframe wirebonded to the first device contacts; a second leadframe wirebonded to the second device contacts; and a plurality of couplers electrically connected between the first and second leadframes.
 18. The package of claim 16 wherein the conductive structure includes a plurality of first package contacts arranged in a first pattern and a plurality of second package contacts arranged in a second pattern, with the second pattern being at least approximately the same as the first pattern.
 19. The package of claim 16 wherein an arrangement of the first device contacts mirrors an arrangement of the second device contacts.
 20. The package of claim 16 wherein at least one the first device contacts includes an input contact and at least one of the second device contacts includes an output contact, further wherein the conductive structure is coupled between the at least one first device contact and the at least one second device contact to direct output signals from the second microfeature device to the first microfeature device.
 21. The package of claim 16 wherein at least a portion of the conductive structure is positioned between the first and second microfeature devices.
 22. The package of claim 16 wherein at least a portion of the conductive structure extends around peripheral edges of the first and second microfeature devices.
 23. A microfeature device package, comprising: a first microfeature device having at least one first device contact; a second microfeature device having at least one second device contact and being stacked relative to the first microfeature device; a first conductive leadframe positioned at least proximate to the first microfeature device, the first leadframe having at least one elongated first leadfinger, the first leadfinger having a first end surface, a second end surface and a generally flat, intermediate surface between the first and second end surfaces, the intermediate surface and the second end surfaces facing in opposite directions, the first leadframe further having a first terminal portion that includes the intermediate surface or the second end surface of the first leadfinger; a first wirebond connected between the at least one first device contact and the at least one first leadfinger; a second conductive leadframe positioned at least proximate to the second microfeature device, the second leadframe having at least one elongated second leadfinger, the second leadfinger having a first end surface, a second end surface and a generally flat, intermediate surface between the first and second end surfaces, the intermediate surface and the second end surfaces facing in opposite directions, the second leadframe further having a second terminal portion that includes the intermediate surface or the second end surface of the second leadfinger; a second wirebond connected between the at least one second device contact and the at least one second leadfinger; a conductive coupler connected between the first and second leadframes; and an encapsulant disposed adjacent to the first and second microfeature devices with the first and second terminal portions accessible to provide electrical coupling with devices external to the package, the first terminal portion being accessible from a first direction for coupling, the second terminal portion being accessible from a second direction for coupling, the second direction being opposite the first direction.
 24. The package of claim 23 wherein the first terminal portion includes a plurality of first package contacts arranged in a first pattern, and wherein the second terminal portion includes a plurality of second package contacts arranged in a second pattern, with the second pattern being different than the first pattern.
 25. The package of claim 23 wherein the first terminal portion includes a plurality of first package contacts arranged in a first pattern, and wherein the second terminal portion includes a plurality of second package contacts arranged in a second pattern, with the second pattern being at least approximately the same as the first pattern.
 26. The package of claim 23 wherein at least one the first device contacts includes an input contact and at least one of the second device contacts includes an output contact, further wherein the conductive structure is coupled between the at least one first device contact and the at least one second device contact to direct output signals from the second microfeature device to the first microfeature device.
 27. The package of clam 23 wherein at least a portion of the conductive structure is positioned between the first and second microfeature devices.
 28. The package of claim 23 wherein at least a portion of the conductive structure extends around peripheral edges of the first and second microfeature devices. 29-45. (canceled) 